1. Field of the Invention
The current invention concerns a method for doping semiconductors used for far infrared hot hole lasers with non-hydrogenic acceptors having binding energies larger than the energy of the laser photons. In particular, the invention involves doping of germanium or silicon crystals with non-hydrogenic acceptor dopants beryllium, zinc or copper introduced into germanium crystals through melt or diffusion. These acceptors do not absorb the laser radiation internally and therefore do not affect laser action. The acceptor dopants allow building of smaller more compact lasers with reduced power dissipation resulting in slower self-heating and much longer pulse lengths. The invention further concerns a far infrared laser comprising germanium crystals doped with double or triple acceptor dopants permitting the doped laser to be tuned continuously from 1 to 4 terahertz and to operate in continuous mode.